The Universe according to DESI results

TL;DR

This paper analyzes the implications of DESI's recent cosmological parameter fit, highlighting potential tensions with the standard model regarding universe expansion, age, and scale factor solutions.

Contribution

It provides a detailed consistency check of DESI's cosmological fit and explores its implications for fundamental cosmological parameters.

Findings

The universe's acceleration differs over time compared to the standard model.

The estimated age of the universe is slightly shorter than the oldest stars.

Analytical and numerical solutions for the scale factor are discussed.

Abstract

The recent fit of cosmological parameters by the Dark Energy Spectroscopic Instrument (DESI) collaboration will have a significant impact on our understanding of the universe. Given its importance, we conduct several consistency checks and draw conclusions from the fit. Specifically, we focus on the following key issues relevant to cosmology: (i) the acceleration of the universe's expansion, which, according to the fit, differs over cosmological time compared to the standard cosmological model; (ii) the age of the universe, which appears slightly shorter than the age of the oldest stars; and (iii) the solution of the scale factor, both numerically and in an approximate analytical form.